The present invention relates to a float chamber and float assembly, and, more particularly, relates to a float chamber and float assembly suitable for a carburetor of an internal combustion engine for an automotive vehicle, which is so constructed as to desirably control the inflow of fluid into the float chamber, even when the automotive vehicle is subjected to sharp acceleration, deceleration, and/or cornering action.
In an automotive vehicle incorporating an internal combustion engine which comprises a carburetor, such a carburetor generally has a float chamber, which is partly filled with fluid fuel such as gasoline, and wherein a float rises up and down by floating on the gasoline within the float chamber, in equilibrium between a downward force exerted by gravity on the mass of the float, and an upward force which is a buoyancy force equal to the weight of a volume of gasoline which is the same as the volume of the float which is below the gasoline surface, i.e. the amount of gasoline displaced by the float.
This float is generally arranged to act upon a valve which controls inflow of gasoline through a gasoline supply passage into the float chamber in such a way that, when the float rises to at least a certain predetermined level within the float chamber, it presses upon the valve so as to close the valve and interrupt further supply of gasoline into the float chamber through the gasoline supply passage; while, on the other hand, when the float is below said certain predetermined position, it releases the valve so as to allow further supply of gasoline through the gasoline supply passage into the float chamber.
Supply of gasoline for the main jet, the idling jet, etc. of the carburetor is typically taken out from a lower part of the float chamber. Thus, as the internal combustion engine of the automotive vehicle operates, withdrawing a flow of gasoline from the gasoline outlet passage, the level of gasoline within the float chamber is maintained substantially constant by the action of the float and the valve cooperating therewith.
However, in prior art float chamber assemblies, a problem has arisen in that if the automotive vehicle is subjected to acceleration force, deceleration force, or turning force, then the fluid surface within the float chamber will become inclined with respect to the float chamber, and, in prior art float chamber and float constructions, this has reduced the buoyancy force exerted upon the float, because the volume of the float which is immersed in the gasoline has become less, assuming that the float is remaining in the above mentioned predetermined position wherein it just closes the valve which controls supply of gasoline through the gasoline inlet passage to the float chamber.
Accordingly, when the vehicle is subjected to such accelerating, decelerating, and/or cornering force, the float has moved downwards within the float chamber, and, accordingly, has opened the valve to allow a greater amount of gasoline to enter into the float chamber than was allowed to enter thereinto when the surface of the gasoline within the float chamber was substantially level with respect thereto.
The presence of this excessive amount of gasoline within the float chamber can be very troublesome. For example, the head or pressure of the gasoline at the gasoline outlet passage of the float chamber will rise in accordance with this excessive amount of gasoline present within the float chamber, and accordingly excess gasoline will disadvantageously be forced out from, for example, the main jet of the carburetor, and will disadvantageously provide an over rich mixture to the internal combustion engine. Further, another problem arises, in that if the carburetor is rather hot there is a danger that the low boiling point components of the excess amount of gasoline within the float chamber will rapidly evaporate at this high temperature, and may cause the so-called `spewing` phenomenon, wherein a foam of gasoline and gasoline vapor is ejected from an air vent at the top of the float chamber.
This air vent is usually communicated to the intake manifold of the internal combustion engine, for purposes of pollution control and fuel economy. Thus, this spewing may well eject a considerable volume of gasoline and gasoline vapor into the inlet manifold of the internal combustion engine, thus providing an extremely rich mixture thereto. This is very wasteful of gasoline, and furthermore produces large quantities of noxious engine emissions, such as HC, CO, smoke, etc., and, in the worst case, may cause stalling of the internal combustion engine.